Smoking
has been on the rise worldwide for the past few decades. With this rise has
come an increase in the number of people suffering from cancer and heart and
lung diseases that are associated with smoking. Many people would like to quit,
but it's incredibly difficult, in part, because tobacco is so addictive. And if
you're a smoker who has switched to a so-called "light" brand to help
you kick the habit, forget it. New research indicates those light brands are
just as addictive as regular cigarettes and just as bad for you.

Researcher
Arthur Brody, with the University of California at Los Angeles, says the
primary addictive substance in tobacco is nicotine. It's only one of thousands
of chemicals in tobacco smoke, but when a person lights up, nicotine floods
chemical receptors in the brain.

"…nicotine
occupies these receptors and desensitizes them, so essentially turns them
off," he says, "and so, for some reason, this results in all of the
reasons that people smoke. You know - the pleasure that they feel or the
reduced anxiety or the little boost in their mood sometimes."

One
strategy people use to quit smoking is to use low-nicotine cigarettes. Brody
recently studied these so-called "light" cigarettes and their effects
on smokers's brains. First, he had people smoke regular cigarettes while they
were in a brain scanner. He could track how many nicotine receptors in the
brain were affected.

"If
they only took one or two puffs of the cigarette, that occupied 50 percent of
this type of nicotine receptor in the brain," Brody says. "Whereas,
if they smoked a full cigarette, it occupies about 88 percent... of those
receptors."

Then
Brody gave people so-called "low-nicotine" cigarettes, which have
even less nictoine than light cigarettes.

"Even
those little-nicotine cigarettes occupied 77 percent of these receptors,"
Brody says. "And so the majority of these receptors get occupied very
easily with very small amounts of nicotine in cigarettes."

Brody
found that even with cigarettes that are supposedly "de-nicotinized,"
about a quarter of the nicotine receptors in smokers' brains were occupied.

"The
problem is that sometimes people buy a light cigarette, and they inhale them
more deeply or they smoke more of them," he says, "and so there
really is no benefit if they do them that way."

Brody
says these findings mean that many smokers who think they're weaning themselves
off tobacco by smoking light or low-nicotine cigarettes might not actually be
getting any benefit from them. He says
that people using these light cigarettes to quit need to be careful about how
much they smoke, or they may need to use a method that reduces the amount of
nicotine they receive in a more reliable way, such as by using nicotine
patches.